Decomposition Free Al₂TiO_5-MgTi₂O₅ Ceramics with Low-Thermal Expansion Coefficient

Abstract

Solid solutions of (1 - x )Al 2 TiO 5 - x MgTi 2 O 5 ( x = 0 - 1) doped with alkaline feldspar were prepared. Thermal decomposition largely depends on the feldspar doping as same as the x value. It was found that decomposition free ceramics over 500 hours of heat treatment at 1100° C in an ambient atmosphere could be obtained for the feldspar-doped ceramics at x > 0.5 with a fracture strength of 33 - 40 MPa and coefficient of thermal expansion of 2.4 - 4.1 × 10 -6 K -1 . A partial decomposition was observed for a compositional range of around x = 0.75. Both composition of the solid solution and an addition of the alkaline feldspar contributed synergistically to improve such thermal and mechanical properties. The decomposition free Al 2 TiO 5 -MgTi 2 O 5 ceramics is expected for variety of high temperature applications including diesel particulate filters.